A lot of people uses the same notebook to access Internet from many places or networks. For example from home and office. If all these networks are using DHCP-assigned IP addresses and network parameters or if you're using different medium (i.e. One at home, wireless at work) then there is no problem. However, if both networks uses static parameters over the same medium, then the only option you're left is manually changing network parameters, as Windows does not allow you to create more than one connection for single hardware (network medium). Hopefully, you can easy your life with a set of simple batch scripts.